The invention provides a nuclear emergency system of a nuclear power plant, and belongs to the technical field of nuclear power plant emergency planning and preparing. The system comprises portable individual emergency devices, a fixed nuclear radiation monitoring device, an emergency refuge and a control center. The portable individual emergency device and the fixed nuclear radiation monitoring device can position and measure current radiation data and send the data to the control center. The control center judges whether leakage happens or not, confirms the accident location and radiation range, and plans the retreating and emergency refuge route according to positions of all workers through summarization and analysis, and sends the information to the corresponding portable individual emergency devices to be displayed on a map through display modules, and safe retreating of the workers is ensured. The system is simple in structure, complete in function, rapid, efficient and high in safety coefficient, greatly improves nuclear emergency reaction capacity and increases the survival rate of the workers on site, and meanwhile can be used as a nuclear emergency command system of the nuclear power plant.